ROOF ANCHORS FOR FACcedilADE ACCESS

ndash A GENERAL OVERVIEW

GREGGREY G COHEN PE AND ROLF A LARSON PE SIMPSON GUMPERTZ amp HEGER INC

41 Seyon Street Waltham MA 02453

Phone 781-907-9344 bull Fax 781-907-9009 bull E-mail ggcohensghcom

27 T H RC I I N T E R N AT I O N A L CO N V E N T I O N A N D T R A D E SH OW bull MAR C H 15 shy 2 0 2012 CO H E N bull 173

ABSTRACT

Building faccedilade access is required for window washing inspection maintenance and repairs Top-down suspended equipment is often the most appropriate access method for a variety of reasons Equipment used for building faccedilade access and personnel performing the work are required to be anchored to the building in some form for safety This presentation will discuss the design installation and periodic inspection and testing of roof anchorages for faccedilade access on existing buildings

SPEAKER

GREGGREY G COHEN PE mdash SIMPSON GUMPERTZ amp HEGER INC shy WALTHAM MA

GREGGREY G COHEN has been with Simpson Gumpertz amp Heger Inc (SGH) for 23 years and has designed such notable structures as University Hospitals of Clevelandrsquos Mather Pavilion and Lerner Tower LeLacheur Baseball Stadium in Lowell MA Richmond County Ballpark in Staten Island NY and renovations and additions to Swedish American Hospital in Rockford IL He has extensive experience managing projects involving structur-al and building envelope investigation rehabilitation strengthening and stabilization demolition sequencing and cost estimating He has evaluated many buildings for faccedilade access equipment as part of inspection and repair projects Cohen has also designed roof anchors for faccedilade access

COAUTHOR

ROLF A LARSON PE mdash SIMPSON GUMPERTZ amp HEGER INC shy WALTHAM MA

ROLF A LARSON is a Senior Staff II ndash Structures at national engineering firm Simpson Gumpertz amp Heger Inc (SGH) He has more than 22 years of experience as a structural design engineer His experience includes design in steel concrete and wood as well as the investigation and renovation of archaic historic structural systems His past work includes the design of new buildings renovation and repair of existing buildings and existing con-dition surveys

174 bull CO H E N 27 T H RC I I N T E R N AT I O N A L CO N V E N T I O N A N D T R A D E SH OW bull MAR C H 15 shy 2 0 2012

ROOF ANCHORS FOR FACcedilADE ACCESS

ndash A GENERAL OVERVIEW

PURPOSE OF FACcedilADE ACCESS ANCHORS

When access to a building faccedilade is nec-essary for maintenance or construction the workers must be provided with safe access to the work Roof-level anchors are an important component to safety There are regulations and standards that apply to the anchors that allow safe access to a faccedilade

1 Personal fall-arrest or lifeline an-chorages are used to support work-ers if they fall from a scaffold or if the scaffold support system fails These are primary systems that will suspend a worker in the air after an equipment failure until an emer-gency response team can complete a rescue

2 Equipment anchorages also called ldquotie-downsrdquo are used to support each end of suspended scaffold in the event of an equipment failure These are secondary systems that keep the equipment from falling from the building in the event of a failure

Anchors used for personal fall arrest or equipment must be designed inspected and tested in conformance with OSHA reg-ulations and IWCA standard

INTRODUCTION WHY ANCHORS ARE NECESSARY

Access to building faccedilades is required for periodic maintenance such as window washing reglazing or caulking and for construction activities such as masonry repair concrete repair and component replacement The use of suspended work platforms supported from cables and tied to anchorages on the roof is a frequently used method of providing worker access to build-ing faccedilades (Photo 1) for construction and maintenance The use of boatswain chairs supported from two independent suspen-sion ropes is a frequently used method of providing worker access to building faccedilades for window-washing maintenance All employees performing work from these sys-tems must use anchored personal fall-pro-

Figure 1

tection systems This paper presents a gen-eral overview of the structural design eval-uation and testing of anchorages for fall-protection systems

There are many forms of suspended scaffolding systems used by contractors all of which must comply with the anchorage

requirements governed by the Occupational Safety amp Health Administration (OSHA a federal agency within the Department of Labor that is responsible for policing work-er safety) and in part by the International Window Cleaning Association (IWCA a pri-vate nonprofit organization that primarily

Photo 1

27 T H RC I I N T E R N AT I O N A L CO N V E N T I O N A N D T R A D E SH OW bull MAR C H 15 shy 2 0 2012 CO H E N bull 175

Parapet hooks

Rooftop appurtenant structures

represents building owners and property managers) Suspended scaffolding and each worker using it must be anchored to the building for safety

Tieback anchors take many forms including parapet hooks rooftop mechani-cal equipment frames cable wraps and permanent roof and wall anchors among others

Suspended scaffolding systems some-times are supported by permanently installed equipment such as davit arms

(Photo 4) Parapet hooks rely on existing faccedilade elements for resisting the required anchor-age loads from the equipment and workers This anchorage type typically loads the original para-

Photo 2

Photo 3

(Photo 2) which are supported in davit bases permanently mounted to the roof structure Alternatively they may be sup-ported by a temporary assembly consisting of outrigger beams with counterweights supported by temporary scaffolding sys-tems mounted on the roof (Photo 3)

DIFFERENT TYPES OF ANCHORAGES

There are a variety of anchorage types commonly used to support equipment dur-ing operation and to arrest falling equip-ment and workers Separate anchorages are required for arresting the fall of the equip-ment and for each worker all of which must be engineered to meet the structural requirements of OSHA and IWCA Anchorages that rely on existing building components require special consideration and attention in order to provide the required safety contemplated by OSHA and IWCA

including variants called parapet clamps or cornice hooks

pet construction in a direction and with a force that was con-sidered in the original design Typically parapets are designed for gravity loading uniform wind and seismic loading only The parapet clamp will typically load the parapet in a direction and with more force than considered in the original design The parapet and its attachment to the building structure must be adequate to safely sup-port the anchorage load in the parapet hook Often building drawings do not show the configuration of the parapet and its con-nection to the building structure in enough detail to properly assess their ability to serve as safe anchorage In this event a detailed field investigation is necessary to determine the parapet construction in enough detail to make such an assessment A structural analysis may also be necessary to confirm that the parapet is capable of supporting the required anchor loads If parapet structures are significantly deterio-rated the impact of the deterioration must be considered in their evaluation Because

they are simple to install contractors often desire to use parapet hooks however they should not be used without confirmation that the parapet can safely support the anchorage loads

such as rooftop-equipment steel platforms (Photo 5) or equipment screen framing are often candidates for anchorages Evaluation of the structural adequacy of the rooftop equipment proposed for an anchorage point should be considered Just as with para-pets such components and their attach-ment to the structure must be adequate to safely carry the anchorage load Review of existing structural drawings will help with confirmation of member sizes and originally proposed connection details Field investi-gation may be necessary to confirm member sizes and connection details If original framing details are not available openings in the roofing may be necessary to confirm the connection of the members to the roof framing Oftenmdashespecially in the case of

176 bull CO H E N 27 T H RC I I N T E R N AT I O N A L CO N V E N T I O N A N D T R A D E SH OW bull MAR C H 15 shy 2 0 2012

Column davit bases

Typical fall protection anchors

support structures for large heavy equip-ment and other similarly robust struc-turesmdasha competent person can readily judge the adequacy of the proposed anchor-age However for less-robust structures such as screen wall framing a review of the design drawings and field investigation may be required to gather enough information to form a rational basis for determining anchorage adequacy If candidate struc-tures are significantly deteriorated the impact of the deterioration must be consid-ered in their evaluation Because they are simple to install contractors often prefer to use rooftop appurtenant structures howev-er they should not be used without confir-mation that the structure can safely sup-port the anchorage loads

also called davit sockets are permanent anchorages struc-turally connected to the existing roof struc-ture (Photo 6) They are con-figured to support building-specific davit arms from which suspended scaffolds are supported These types of systems are load-rated by the manufacturer Detailed infor-mation regarding the load rat-ing should be fixed to the equipment along with the name of the manufacturer Regular inspections are typi-cally performed on perma-nent systems in order to have certification for use Workers should request the inspection documentation to confirm that the equipment is certified for use If the certification has expired recertification is nec-essary Recertification re-quires a detailed investigation to make observations of the connection between davit sockets and the building structure and load testing Structural cal-culations may be required to determine capacity if rating information is not available

(Photo 7) commonly called roof davits lifeline anchors or tieback anchors Fall protection anchors typically consist of a round steel pipe sec-tion with a steel eyelet to provide a location for cable or life-line tie off A steel base plate typically is mechanically anchored to the structure to provide a positive connection These systems often are incorporated into the design of the building or retrofitted to an existing building In some appli-cations connections that extend through the slab are neces-sary to resist the required loading Retrofit installations require knowledge of the existing structural system either through the availability of original drawings or through a

Photo 4

Photo 5

Photo 6

27 T H RC I I N T E R N AT I O N A L CO N V E N T I O N A N D T R A D E SH OW bull MAR C H 15 shy 2 0 2012 CO H E N bull 177

Wall anchors

Horizontal life-lines

Photo 7

judge the adequacy of the proposed anchor-age However for less-robust wall sys-tems such as brick veneer on metal-stud backup a review of the design drawings and field investiga-tion may be required to gather enough information to form a rational basis for determining anchor-age adequacy

also called

detailed field investigation are another commonly

used anchorage (Photos 8 and 9) typically consisting of a steel eyelet shop-welded to a steel plate with mechanical anchors to pro-vide a connection to the existing structure In a retrofit application knowledge of the existing wall structure is necessary to deter-mine the adequacy of the wall structure Typical roof-level walls are designed for wind and seismic loading only Anchors will impart forces on the wall that typically are not considered in the wall design Often especially in the case of cast-in-place con-crete walls and other similarly robust wall systems a competent person can readily

cable wraps are hor-izontal cables used as

anchorages for both suspended scaffold tiebacks and lifelines Cables are run either between steel pipe anchorages or around other roof appurtenant structures such as penthouses The anchorages and cables both must be designed to support required loading Horizontal cable wraps can be used for multiple devices provided they are designed for the loads imparted by multiple components The analysis of this type of configuration must account for the result-ing forces which are typically quite high Tight cable wraps can be problematic since the small relative deformations and small angularity of the cable wrap imparted by the loaded tiebacks and lifelines generate

very high forces in the wrap It may be necessary to have a ldquolooserdquo wrap but one that

Photo 9

is supported in a way that does not allow excessive movement before it provides resis-tance for the tieback or lifeline Contractors installing cable-wrap systems must under-stand the structural capacity of the existing building components that are wrapped A field investigation may be necessary to veri-fy that the components are structurally anchored to the existing building with the capacity to support the loads imparted by the cable wrap A structural engineer or other competent person should review the installation prior to use

Other types of manufactured anchor devices are available on the market They will not be discussed in this paper

INDUSTRY GUIDELINES OSHA which began publishing safety

standards in 1971 outlines its require-ments in regulations or standards These standards are organized by the type of installation (permanent or temporary) and by the type of worker activity (maintenance or construction) The standards are as fol-lows

bull Temporary suspended scaffolding for general industry use (ie main-tenance) is governed by OSHA 29 CFR Part 1910 Subpart D Standard 191028 Safety Requireshyments for Scaffolding

bull Permanent powered platforms for general industry use (ie mainte-nance) are governed by OSHA 29 CFR Part 1910 Subpart F Stan-dard 191066 Powered Platforms for Building Maintenance and Appendix C

bull Temporary suspended scaffolding

27 T H RC I I N T E R N AT I O N A L CO N V E N T I O N

Photo 8

178 bull CO H E N A N D T R A D E SH OW bull MAR C H 15 shy 2 0 2012

OSHA Requirements

Standard 191028

Standard 191066

Standard 1926

for construction is governed by OSHA 29 CFR 1926 Subpart L Scaffolds Standards 1926450 1926451 and 1926452 and asso-ciated appendices as referenced in each section of the standard

bull Fall protection for construction with the use of temporary suspended scaffolding is governed by 29 CFR 1926 Subpart M Fall Protection

All OSHA standards are available online at wwwoshagov

In addition to these standards OSHA publishes official responses to questions submitted in writing by the public that are considered important clarifications to the published standard Standard Interpretashytions is an important resource for resolving unstated or unclear provisions of the OSHA standards Standard Interpretations is also available online

In 2001 the IWCA published the first edition of the ANSIIWCA I-141 Window Cleaning Safety Standard The standard includes guidelines for access to faccedilades for maintenance-type activities The standard provides detailed safety guidelines for the use of window-cleaning access equipment including the design certification and test-ing requirements for anchorages

The IWCA standard is available for pur-chase online at wwwiwcaorg

CONSTRUCTION VERSUS MAINTENANCE

OSHA Standard 191066(a) states ldquoBuilding maintenance includes but is not limited to such tasks as window cleaning caulking metal polishing and reglazingrdquo A Standard Interpretation dated 11182003 clarifies that work is considered mainte-nance if it involves ldquokeeping equipment working in its existing state or preventing its failure or decline In addition the con-cept of one-for-one replacement versus improvement as well as the scale and com-plexity of the project are relevantrdquo

According to OSHA the distinction appears to hinge on whether an improve-ment or an alteration is being made and also on the size of the project It is possible to replace components of a building one for one and still have the work be considered a construction activity if the magnitude of the project is of long duration or financially sig-nificant Since it may be unclear if a project represents ldquoconstructionrdquo or ldquomaintenancerdquo and since OSHA is not policing on the per-

mitting side of the project the conservative decision might be to follow the OSHA stan-dards that are the most demanding This would result in the designer following the structural requirements of either OSHA Standard 191066 or 1926 which are essentially identical as Standard 191028 lacks specific design requirements

DESIGN REQUIREMENTS

The following are excerpts from the OSHA standards that are related to the design of roof access anchors

191028(a)(4) Scaffolds and their components shall be capable of sup-porting without failure at least four times the maximum intended load

The intended load is either the load from the personal fall protection line or the sus-pended scaffold tieback line

191066(f)(3)(ii)(C) Each trans-portable outrigger shall be secured with a tie-down to a verified anchor-age on the building during the entire period of its use The anchorage shall be designed to have a stability factor of not less than four against overturning or upsetting of the out-rigger

The load that causes the overturning is not defined by this provision

191066(f)(3)(iii)(A) Davits Every davit installationmdashfixed or trans-portable rotatable or nonrotatablemdash shall be designed and installed to insure [sic] that it has a stability fac-tor against overturning of not less than four

The load that causes the overturning moment is not defined in this provision

191066 Appendix C I(c)(10) Anch-orages to which personal fall arrest equipment is attached shall be capable of supporting at least 5000 pounds per employee attached or shall be designed installed and used as part of a complete personal

fall arrest system which [sic] main-tains a safety factor of at least two under the supervision of a qualified person

The 5000-lb load is interpreted as an ultimate load The components that resist this load shall do so without failure Complete fall arrest systems are not the subject of this paper

1926451(a)(1) Except as provided in paragraphs (a)(2) (a)(3) (a)(4) (a)(5) and (g) of this section each scaffold and scaffold component shall be capable of supporting without fail-ure its own weight and at least four times the maximum intended load applied or transmitted to it

This provision is for the suspended scaf-fold equipment including the platform and the platform components

1926451(a)(2) Direct connections to roofs and floors and counterweights used to balance adjustable suspen-sion scaffolds shall be capable of resisting at least four times the tip-ping moment imposed by the scaf-fold operating at the rated load of the hoist or 15 (minimum) times the tipping moment imposed by the scaffold operating at the stall load of the hoist whichever is greater

This provision is used to determine the amount of the counterweights needed for the back span of the suspended scaffold outrigger beams The stall load of the hoist motor can be obtained from the hoist man-ufacturer

1926451(d)(1) All suspension scaf-fold support devices such as outrig-ger beams cornice hooks parapet clamps and similar devices shall rest on surfaces capable of support-ing at least four times the load imposed on them by the scaffold operating at the rated load of the hoist (or at least 15 times the load imposed on them by the scaffold at the stall capacity of the hoist whichever is greater)

This provision provides design criteria

27 T H RC I I N T E R N AT I O N A L CO N V E N T I O N A N D T R A D E SH OW bull MAR C H 15 shy 2 0 2012 CO H E N bull 179

Parapet hooks

Rooftop appurtenant structures

represents building owners and property managers) Suspended scaffolding and each worker using it must be anchored to the building for safety

Tieback anchors take many forms including parapet hooks rooftop mechani-cal equipment frames cable wraps and permanent roof and wall anchors among others

Suspended scaffolding systems some-times are supported by permanently installed equipment such as davit arms

(Photo 4) Parapet hooks rely on existing faccedilade elements for resisting the required anchor-age loads from the equipment and workers This anchorage type typically loads the original para-

Photo 2

Photo 3

(Photo 2) which are supported in davit bases permanently mounted to the roof structure Alternatively they may be sup-ported by a temporary assembly consisting of outrigger beams with counterweights supported by temporary scaffolding sys-tems mounted on the roof (Photo 3)

DIFFERENT TYPES OF ANCHORAGES

There are a variety of anchorage types commonly used to support equipment dur-ing operation and to arrest falling equip-ment and workers Separate anchorages are required for arresting the fall of the equip-ment and for each worker all of which must be engineered to meet the structural requirements of OSHA and IWCA Anchorages that rely on existing building components require special consideration and attention in order to provide the required safety contemplated by OSHA and IWCA

including variants called parapet clamps or cornice hooks

pet construction in a direction and with a force that was con-sidered in the original design Typically parapets are designed for gravity loading uniform wind and seismic loading only The parapet clamp will typically load the parapet in a direction and with more force than considered in the original design The parapet and its attachment to the building structure must be adequate to safely sup-port the anchorage load in the parapet hook Often building drawings do not show the configuration of the parapet and its con-nection to the building structure in enough detail to properly assess their ability to serve as safe anchorage In this event a detailed field investigation is necessary to determine the parapet construction in enough detail to make such an assessment A structural analysis may also be necessary to confirm that the parapet is capable of supporting the required anchor loads If parapet structures are significantly deterio-rated the impact of the deterioration must be considered in their evaluation Because

they are simple to install contractors often desire to use parapet hooks however they should not be used without confirmation that the parapet can safely support the anchorage loads

such as rooftop-equipment steel platforms (Photo 5) or equipment screen framing are often candidates for anchorages Evaluation of the structural adequacy of the rooftop equipment proposed for an anchorage point should be considered Just as with para-pets such components and their attach-ment to the structure must be adequate to safely carry the anchorage load Review of existing structural drawings will help with confirmation of member sizes and originally proposed connection details Field investi-gation may be necessary to confirm member sizes and connection details If original framing details are not available openings in the roofing may be necessary to confirm the connection of the members to the roof framing Oftenmdashespecially in the case of

176 bull CO H E N 27 T H RC I I N T E R N AT I O N A L CO N V E N T I O N A N D T R A D E SH OW bull MAR C H 15 shy 2 0 2012

Column davit bases

Typical fall protection anchors

support structures for large heavy equip-ment and other similarly robust struc-turesmdasha competent person can readily judge the adequacy of the proposed anchor-age However for less-robust structures such as screen wall framing a review of the design drawings and field investigation may be required to gather enough information to form a rational basis for determining anchorage adequacy If candidate struc-tures are significantly deteriorated the impact of the deterioration must be consid-ered in their evaluation Because they are simple to install contractors often prefer to use rooftop appurtenant structures howev-er they should not be used without confir-mation that the structure can safely sup-port the anchorage loads

also called davit sockets are permanent anchorages struc-turally connected to the existing roof struc-ture (Photo 6) They are con-figured to support building-specific davit arms from which suspended scaffolds are supported These types of systems are load-rated by the manufacturer Detailed infor-mation regarding the load rat-ing should be fixed to the equipment along with the name of the manufacturer Regular inspections are typi-cally performed on perma-nent systems in order to have certification for use Workers should request the inspection documentation to confirm that the equipment is certified for use If the certification has expired recertification is nec-essary Recertification re-quires a detailed investigation to make observations of the connection between davit sockets and the building structure and load testing Structural cal-culations may be required to determine capacity if rating information is not available

(Photo 7) commonly called roof davits lifeline anchors or tieback anchors Fall protection anchors typically consist of a round steel pipe sec-tion with a steel eyelet to provide a location for cable or life-line tie off A steel base plate typically is mechanically anchored to the structure to provide a positive connection These systems often are incorporated into the design of the building or retrofitted to an existing building In some appli-cations connections that extend through the slab are neces-sary to resist the required loading Retrofit installations require knowledge of the existing structural system either through the availability of original drawings or through a

Photo 4

Photo 5

Photo 6

27 T H RC I I N T E R N AT I O N A L CO N V E N T I O N A N D T R A D E SH OW bull MAR C H 15 shy 2 0 2012 CO H E N bull 177

Wall anchors

Horizontal life-lines

Photo 7

judge the adequacy of the proposed anchor-age However for less-robust wall sys-tems such as brick veneer on metal-stud backup a review of the design drawings and field investiga-tion may be required to gather enough information to form a rational basis for determining anchor-age adequacy

also called

detailed field investigation are another commonly

used anchorage (Photos 8 and 9) typically consisting of a steel eyelet shop-welded to a steel plate with mechanical anchors to pro-vide a connection to the existing structure In a retrofit application knowledge of the existing wall structure is necessary to deter-mine the adequacy of the wall structure Typical roof-level walls are designed for wind and seismic loading only Anchors will impart forces on the wall that typically are not considered in the wall design Often especially in the case of cast-in-place con-crete walls and other similarly robust wall systems a competent person can readily

cable wraps are hor-izontal cables used as

anchorages for both suspended scaffold tiebacks and lifelines Cables are run either between steel pipe anchorages or around other roof appurtenant structures such as penthouses The anchorages and cables both must be designed to support required loading Horizontal cable wraps can be used for multiple devices provided they are designed for the loads imparted by multiple components The analysis of this type of configuration must account for the result-ing forces which are typically quite high Tight cable wraps can be problematic since the small relative deformations and small angularity of the cable wrap imparted by the loaded tiebacks and lifelines generate

very high forces in the wrap It may be necessary to have a ldquolooserdquo wrap but one that

Photo 9

is supported in a way that does not allow excessive movement before it provides resis-tance for the tieback or lifeline Contractors installing cable-wrap systems must under-stand the structural capacity of the existing building components that are wrapped A field investigation may be necessary to veri-fy that the components are structurally anchored to the existing building with the capacity to support the loads imparted by the cable wrap A structural engineer or other competent person should review the installation prior to use

Other types of manufactured anchor devices are available on the market They will not be discussed in this paper

INDUSTRY GUIDELINES OSHA which began publishing safety

standards in 1971 outlines its require-ments in regulations or standards These standards are organized by the type of installation (permanent or temporary) and by the type of worker activity (maintenance or construction) The standards are as fol-lows

bull Temporary suspended scaffolding for general industry use (ie main-tenance) is governed by OSHA 29 CFR Part 1910 Subpart D Standard 191028 Safety Requireshyments for Scaffolding

bull Permanent powered platforms for general industry use (ie mainte-nance) are governed by OSHA 29 CFR Part 1910 Subpart F Stan-dard 191066 Powered Platforms for Building Maintenance and Appendix C

bull Temporary suspended scaffolding

27 T H RC I I N T E R N AT I O N A L CO N V E N T I O N

Photo 8

178 bull CO H E N A N D T R A D E SH OW bull MAR C H 15 shy 2 0 2012

OSHA Requirements

Standard 191028

Standard 191066

Standard 1926

for construction is governed by OSHA 29 CFR 1926 Subpart L Scaffolds Standards 1926450 1926451 and 1926452 and asso-ciated appendices as referenced in each section of the standard

bull Fall protection for construction with the use of temporary suspended scaffolding is governed by 29 CFR 1926 Subpart M Fall Protection

All OSHA standards are available online at wwwoshagov

In addition to these standards OSHA publishes official responses to questions submitted in writing by the public that are considered important clarifications to the published standard Standard Interpretashytions is an important resource for resolving unstated or unclear provisions of the OSHA standards Standard Interpretations is also available online

In 2001 the IWCA published the first edition of the ANSIIWCA I-141 Window Cleaning Safety Standard The standard includes guidelines for access to faccedilades for maintenance-type activities The standard provides detailed safety guidelines for the use of window-cleaning access equipment including the design certification and test-ing requirements for anchorages

The IWCA standard is available for pur-chase online at wwwiwcaorg

CONSTRUCTION VERSUS MAINTENANCE

OSHA Standard 191066(a) states ldquoBuilding maintenance includes but is not limited to such tasks as window cleaning caulking metal polishing and reglazingrdquo A Standard Interpretation dated 11182003 clarifies that work is considered mainte-nance if it involves ldquokeeping equipment working in its existing state or preventing its failure or decline In addition the con-cept of one-for-one replacement versus improvement as well as the scale and com-plexity of the project are relevantrdquo

According to OSHA the distinction appears to hinge on whether an improve-ment or an alteration is being made and also on the size of the project It is possible to replace components of a building one for one and still have the work be considered a construction activity if the magnitude of the project is of long duration or financially sig-nificant Since it may be unclear if a project represents ldquoconstructionrdquo or ldquomaintenancerdquo and since OSHA is not policing on the per-

mitting side of the project the conservative decision might be to follow the OSHA stan-dards that are the most demanding This would result in the designer following the structural requirements of either OSHA Standard 191066 or 1926 which are essentially identical as Standard 191028 lacks specific design requirements

DESIGN REQUIREMENTS

The following are excerpts from the OSHA standards that are related to the design of roof access anchors

191028(a)(4) Scaffolds and their components shall be capable of sup-porting without failure at least four times the maximum intended load

The intended load is either the load from the personal fall protection line or the sus-pended scaffold tieback line

191066(f)(3)(ii)(C) Each trans-portable outrigger shall be secured with a tie-down to a verified anchor-age on the building during the entire period of its use The anchorage shall be designed to have a stability factor of not less than four against overturning or upsetting of the out-rigger

The load that causes the overturning is not defined by this provision

191066(f)(3)(iii)(A) Davits Every davit installationmdashfixed or trans-portable rotatable or nonrotatablemdash shall be designed and installed to insure [sic] that it has a stability fac-tor against overturning of not less than four

The load that causes the overturning moment is not defined in this provision

191066 Appendix C I(c)(10) Anch-orages to which personal fall arrest equipment is attached shall be capable of supporting at least 5000 pounds per employee attached or shall be designed installed and used as part of a complete personal

fall arrest system which [sic] main-tains a safety factor of at least two under the supervision of a qualified person

The 5000-lb load is interpreted as an ultimate load The components that resist this load shall do so without failure Complete fall arrest systems are not the subject of this paper

1926451(a)(1) Except as provided in paragraphs (a)(2) (a)(3) (a)(4) (a)(5) and (g) of this section each scaffold and scaffold component shall be capable of supporting without fail-ure its own weight and at least four times the maximum intended load applied or transmitted to it

This provision is for the suspended scaf-fold equipment including the platform and the platform components

1926451(a)(2) Direct connections to roofs and floors and counterweights used to balance adjustable suspen-sion scaffolds shall be capable of resisting at least four times the tip-ping moment imposed by the scaf-fold operating at the rated load of the hoist or 15 (minimum) times the tipping moment imposed by the scaffold operating at the stall load of the hoist whichever is greater

This provision is used to determine the amount of the counterweights needed for the back span of the suspended scaffold outrigger beams The stall load of the hoist motor can be obtained from the hoist man-ufacturer

1926451(d)(1) All suspension scaf-fold support devices such as outrig-ger beams cornice hooks parapet clamps and similar devices shall rest on surfaces capable of support-ing at least four times the load imposed on them by the scaffold operating at the rated load of the hoist (or at least 15 times the load imposed on them by the scaffold at the stall capacity of the hoist whichever is greater)

This provision provides design criteria

27 T H RC I I N T E R N AT I O N A L CO N V E N T I O N A N D T R A D E SH OW bull MAR C H 15 shy 2 0 2012 CO H E N bull 179

Column davit bases

Typical fall protection anchors

support structures for large heavy equip-ment and other similarly robust struc-turesmdasha competent person can readily judge the adequacy of the proposed anchor-age However for less-robust structures such as screen wall framing a review of the design drawings and field investigation may be required to gather enough information to form a rational basis for determining anchorage adequacy If candidate struc-tures are significantly deteriorated the impact of the deterioration must be consid-ered in their evaluation Because they are simple to install contractors often prefer to use rooftop appurtenant structures howev-er they should not be used without confir-mation that the structure can safely sup-port the anchorage loads

also called davit sockets are permanent anchorages struc-turally connected to the existing roof struc-ture (Photo 6) They are con-figured to support building-specific davit arms from which suspended scaffolds are supported These types of systems are load-rated by the manufacturer Detailed infor-mation regarding the load rat-ing should be fixed to the equipment along with the name of the manufacturer Regular inspections are typi-cally performed on perma-nent systems in order to have certification for use Workers should request the inspection documentation to confirm that the equipment is certified for use If the certification has expired recertification is nec-essary Recertification re-quires a detailed investigation to make observations of the connection between davit sockets and the building structure and load testing Structural cal-culations may be required to determine capacity if rating information is not available

(Photo 7) commonly called roof davits lifeline anchors or tieback anchors Fall protection anchors typically consist of a round steel pipe sec-tion with a steel eyelet to provide a location for cable or life-line tie off A steel base plate typically is mechanically anchored to the structure to provide a positive connection These systems often are incorporated into the design of the building or retrofitted to an existing building In some appli-cations connections that extend through the slab are neces-sary to resist the required loading Retrofit installations require knowledge of the existing structural system either through the availability of original drawings or through a

Photo 4

Photo 5

Photo 6

27 T H RC I I N T E R N AT I O N A L CO N V E N T I O N A N D T R A D E SH OW bull MAR C H 15 shy 2 0 2012 CO H E N bull 177

Wall anchors

Horizontal life-lines

Photo 7

judge the adequacy of the proposed anchor-age However for less-robust wall sys-tems such as brick veneer on metal-stud backup a review of the design drawings and field investiga-tion may be required to gather enough information to form a rational basis for determining anchor-age adequacy

also called

detailed field investigation are another commonly

used anchorage (Photos 8 and 9) typically consisting of a steel eyelet shop-welded to a steel plate with mechanical anchors to pro-vide a connection to the existing structure In a retrofit application knowledge of the existing wall structure is necessary to deter-mine the adequacy of the wall structure Typical roof-level walls are designed for wind and seismic loading only Anchors will impart forces on the wall that typically are not considered in the wall design Often especially in the case of cast-in-place con-crete walls and other similarly robust wall systems a competent person can readily

cable wraps are hor-izontal cables used as

anchorages for both suspended scaffold tiebacks and lifelines Cables are run either between steel pipe anchorages or around other roof appurtenant structures such as penthouses The anchorages and cables both must be designed to support required loading Horizontal cable wraps can be used for multiple devices provided they are designed for the loads imparted by multiple components The analysis of this type of configuration must account for the result-ing forces which are typically quite high Tight cable wraps can be problematic since the small relative deformations and small angularity of the cable wrap imparted by the loaded tiebacks and lifelines generate

very high forces in the wrap It may be necessary to have a ldquolooserdquo wrap but one that

Photo 9

is supported in a way that does not allow excessive movement before it provides resis-tance for the tieback or lifeline Contractors installing cable-wrap systems must under-stand the structural capacity of the existing building components that are wrapped A field investigation may be necessary to veri-fy that the components are structurally anchored to the existing building with the capacity to support the loads imparted by the cable wrap A structural engineer or other competent person should review the installation prior to use

Other types of manufactured anchor devices are available on the market They will not be discussed in this paper

INDUSTRY GUIDELINES OSHA which began publishing safety

standards in 1971 outlines its require-ments in regulations or standards These standards are organized by the type of installation (permanent or temporary) and by the type of worker activity (maintenance or construction) The standards are as fol-lows

bull Temporary suspended scaffolding for general industry use (ie main-tenance) is governed by OSHA 29 CFR Part 1910 Subpart D Standard 191028 Safety Requireshyments for Scaffolding

bull Permanent powered platforms for general industry use (ie mainte-nance) are governed by OSHA 29 CFR Part 1910 Subpart F Stan-dard 191066 Powered Platforms for Building Maintenance and Appendix C

bull Temporary suspended scaffolding

27 T H RC I I N T E R N AT I O N A L CO N V E N T I O N

Photo 8

178 bull CO H E N A N D T R A D E SH OW bull MAR C H 15 shy 2 0 2012

OSHA Requirements

Standard 191028

Standard 191066

Standard 1926

for construction is governed by OSHA 29 CFR 1926 Subpart L Scaffolds Standards 1926450 1926451 and 1926452 and asso-ciated appendices as referenced in each section of the standard

bull Fall protection for construction with the use of temporary suspended scaffolding is governed by 29 CFR 1926 Subpart M Fall Protection

All OSHA standards are available online at wwwoshagov

In addition to these standards OSHA publishes official responses to questions submitted in writing by the public that are considered important clarifications to the published standard Standard Interpretashytions is an important resource for resolving unstated or unclear provisions of the OSHA standards Standard Interpretations is also available online

In 2001 the IWCA published the first edition of the ANSIIWCA I-141 Window Cleaning Safety Standard The standard includes guidelines for access to faccedilades for maintenance-type activities The standard provides detailed safety guidelines for the use of window-cleaning access equipment including the design certification and test-ing requirements for anchorages

The IWCA standard is available for pur-chase online at wwwiwcaorg

CONSTRUCTION VERSUS MAINTENANCE

OSHA Standard 191066(a) states ldquoBuilding maintenance includes but is not limited to such tasks as window cleaning caulking metal polishing and reglazingrdquo A Standard Interpretation dated 11182003 clarifies that work is considered mainte-nance if it involves ldquokeeping equipment working in its existing state or preventing its failure or decline In addition the con-cept of one-for-one replacement versus improvement as well as the scale and com-plexity of the project are relevantrdquo

According to OSHA the distinction appears to hinge on whether an improve-ment or an alteration is being made and also on the size of the project It is possible to replace components of a building one for one and still have the work be considered a construction activity if the magnitude of the project is of long duration or financially sig-nificant Since it may be unclear if a project represents ldquoconstructionrdquo or ldquomaintenancerdquo and since OSHA is not policing on the per-

mitting side of the project the conservative decision might be to follow the OSHA stan-dards that are the most demanding This would result in the designer following the structural requirements of either OSHA Standard 191066 or 1926 which are essentially identical as Standard 191028 lacks specific design requirements

DESIGN REQUIREMENTS

The following are excerpts from the OSHA standards that are related to the design of roof access anchors

191028(a)(4) Scaffolds and their components shall be capable of sup-porting without failure at least four times the maximum intended load

The intended load is either the load from the personal fall protection line or the sus-pended scaffold tieback line

191066(f)(3)(ii)(C) Each trans-portable outrigger shall be secured with a tie-down to a verified anchor-age on the building during the entire period of its use The anchorage shall be designed to have a stability factor of not less than four against overturning or upsetting of the out-rigger

The load that causes the overturning is not defined by this provision

191066(f)(3)(iii)(A) Davits Every davit installationmdashfixed or trans-portable rotatable or nonrotatablemdash shall be designed and installed to insure [sic] that it has a stability fac-tor against overturning of not less than four

The load that causes the overturning moment is not defined in this provision

191066 Appendix C I(c)(10) Anch-orages to which personal fall arrest equipment is attached shall be capable of supporting at least 5000 pounds per employee attached or shall be designed installed and used as part of a complete personal

fall arrest system which [sic] main-tains a safety factor of at least two under the supervision of a qualified person

The 5000-lb load is interpreted as an ultimate load The components that resist this load shall do so without failure Complete fall arrest systems are not the subject of this paper

1926451(a)(1) Except as provided in paragraphs (a)(2) (a)(3) (a)(4) (a)(5) and (g) of this section each scaffold and scaffold component shall be capable of supporting without fail-ure its own weight and at least four times the maximum intended load applied or transmitted to it

This provision is for the suspended scaf-fold equipment including the platform and the platform components

1926451(a)(2) Direct connections to roofs and floors and counterweights used to balance adjustable suspen-sion scaffolds shall be capable of resisting at least four times the tip-ping moment imposed by the scaf-fold operating at the rated load of the hoist or 15 (minimum) times the tipping moment imposed by the scaffold operating at the stall load of the hoist whichever is greater

This provision is used to determine the amount of the counterweights needed for the back span of the suspended scaffold outrigger beams The stall load of the hoist motor can be obtained from the hoist man-ufacturer

1926451(d)(1) All suspension scaf-fold support devices such as outrig-ger beams cornice hooks parapet clamps and similar devices shall rest on surfaces capable of support-ing at least four times the load imposed on them by the scaffold operating at the rated load of the hoist (or at least 15 times the load imposed on them by the scaffold at the stall capacity of the hoist whichever is greater)

This provision provides design criteria

27 T H RC I I N T E R N AT I O N A L CO N V E N T I O N A N D T R A D E SH OW bull MAR C H 15 shy 2 0 2012 CO H E N bull 179

Wall anchors

Horizontal life-lines

Photo 7

judge the adequacy of the proposed anchor-age However for less-robust wall sys-tems such as brick veneer on metal-stud backup a review of the design drawings and field investiga-tion may be required to gather enough information to form a rational basis for determining anchor-age adequacy

also called

detailed field investigation are another commonly

used anchorage (Photos 8 and 9) typically consisting of a steel eyelet shop-welded to a steel plate with mechanical anchors to pro-vide a connection to the existing structure In a retrofit application knowledge of the existing wall structure is necessary to deter-mine the adequacy of the wall structure Typical roof-level walls are designed for wind and seismic loading only Anchors will impart forces on the wall that typically are not considered in the wall design Often especially in the case of cast-in-place con-crete walls and other similarly robust wall systems a competent person can readily

cable wraps are hor-izontal cables used as

anchorages for both suspended scaffold tiebacks and lifelines Cables are run either between steel pipe anchorages or around other roof appurtenant structures such as penthouses The anchorages and cables both must be designed to support required loading Horizontal cable wraps can be used for multiple devices provided they are designed for the loads imparted by multiple components The analysis of this type of configuration must account for the result-ing forces which are typically quite high Tight cable wraps can be problematic since the small relative deformations and small angularity of the cable wrap imparted by the loaded tiebacks and lifelines generate

very high forces in the wrap It may be necessary to have a ldquolooserdquo wrap but one that

Photo 9

is supported in a way that does not allow excessive movement before it provides resis-tance for the tieback or lifeline Contractors installing cable-wrap systems must under-stand the structural capacity of the existing building components that are wrapped A field investigation may be necessary to veri-fy that the components are structurally anchored to the existing building with the capacity to support the loads imparted by the cable wrap A structural engineer or other competent person should review the installation prior to use

Other types of manufactured anchor devices are available on the market They will not be discussed in this paper

INDUSTRY GUIDELINES OSHA which began publishing safety

standards in 1971 outlines its require-ments in regulations or standards These standards are organized by the type of installation (permanent or temporary) and by the type of worker activity (maintenance or construction) The standards are as fol-lows

bull Temporary suspended scaffolding for general industry use (ie main-tenance) is governed by OSHA 29 CFR Part 1910 Subpart D Standard 191028 Safety Requireshyments for Scaffolding

bull Permanent powered platforms for general industry use (ie mainte-nance) are governed by OSHA 29 CFR Part 1910 Subpart F Stan-dard 191066 Powered Platforms for Building Maintenance and Appendix C

bull Temporary suspended scaffolding

27 T H RC I I N T E R N AT I O N A L CO N V E N T I O N

Photo 8

178 bull CO H E N A N D T R A D E SH OW bull MAR C H 15 shy 2 0 2012

OSHA Requirements

Standard 191028

Standard 191066

Standard 1926

for construction is governed by OSHA 29 CFR 1926 Subpart L Scaffolds Standards 1926450 1926451 and 1926452 and asso-ciated appendices as referenced in each section of the standard

bull Fall protection for construction with the use of temporary suspended scaffolding is governed by 29 CFR 1926 Subpart M Fall Protection

All OSHA standards are available online at wwwoshagov

In addition to these standards OSHA publishes official responses to questions submitted in writing by the public that are considered important clarifications to the published standard Standard Interpretashytions is an important resource for resolving unstated or unclear provisions of the OSHA standards Standard Interpretations is also available online

In 2001 the IWCA published the first edition of the ANSIIWCA I-141 Window Cleaning Safety Standard The standard includes guidelines for access to faccedilades for maintenance-type activities The standard provides detailed safety guidelines for the use of window-cleaning access equipment including the design certification and test-ing requirements for anchorages

The IWCA standard is available for pur-chase online at wwwiwcaorg

CONSTRUCTION VERSUS MAINTENANCE

OSHA Standard 191066(a) states ldquoBuilding maintenance includes but is not limited to such tasks as window cleaning caulking metal polishing and reglazingrdquo A Standard Interpretation dated 11182003 clarifies that work is considered mainte-nance if it involves ldquokeeping equipment working in its existing state or preventing its failure or decline In addition the con-cept of one-for-one replacement versus improvement as well as the scale and com-plexity of the project are relevantrdquo

According to OSHA the distinction appears to hinge on whether an improve-ment or an alteration is being made and also on the size of the project It is possible to replace components of a building one for one and still have the work be considered a construction activity if the magnitude of the project is of long duration or financially sig-nificant Since it may be unclear if a project represents ldquoconstructionrdquo or ldquomaintenancerdquo and since OSHA is not policing on the per-

mitting side of the project the conservative decision might be to follow the OSHA stan-dards that are the most demanding This would result in the designer following the structural requirements of either OSHA Standard 191066 or 1926 which are essentially identical as Standard 191028 lacks specific design requirements

DESIGN REQUIREMENTS

The following are excerpts from the OSHA standards that are related to the design of roof access anchors

191028(a)(4) Scaffolds and their components shall be capable of sup-porting without failure at least four times the maximum intended load

The intended load is either the load from the personal fall protection line or the sus-pended scaffold tieback line

191066(f)(3)(ii)(C) Each trans-portable outrigger shall be secured with a tie-down to a verified anchor-age on the building during the entire period of its use The anchorage shall be designed to have a stability factor of not less than four against overturning or upsetting of the out-rigger

The load that causes the overturning is not defined by this provision

191066(f)(3)(iii)(A) Davits Every davit installationmdashfixed or trans-portable rotatable or nonrotatablemdash shall be designed and installed to insure [sic] that it has a stability fac-tor against overturning of not less than four

The load that causes the overturning moment is not defined in this provision

191066 Appendix C I(c)(10) Anch-orages to which personal fall arrest equipment is attached shall be capable of supporting at least 5000 pounds per employee attached or shall be designed installed and used as part of a complete personal

fall arrest system which [sic] main-tains a safety factor of at least two under the supervision of a qualified person

The 5000-lb load is interpreted as an ultimate load The components that resist this load shall do so without failure Complete fall arrest systems are not the subject of this paper

1926451(a)(1) Except as provided in paragraphs (a)(2) (a)(3) (a)(4) (a)(5) and (g) of this section each scaffold and scaffold component shall be capable of supporting without fail-ure its own weight and at least four times the maximum intended load applied or transmitted to it

This provision is for the suspended scaf-fold equipment including the platform and the platform components

1926451(a)(2) Direct connections to roofs and floors and counterweights used to balance adjustable suspen-sion scaffolds shall be capable of resisting at least four times the tip-ping moment imposed by the scaf-fold operating at the rated load of the hoist or 15 (minimum) times the tipping moment imposed by the scaffold operating at the stall load of the hoist whichever is greater

This provision is used to determine the amount of the counterweights needed for the back span of the suspended scaffold outrigger beams The stall load of the hoist motor can be obtained from the hoist man-ufacturer

1926451(d)(1) All suspension scaf-fold support devices such as outrig-ger beams cornice hooks parapet clamps and similar devices shall rest on surfaces capable of support-ing at least four times the load imposed on them by the scaffold operating at the rated load of the hoist (or at least 15 times the load imposed on them by the scaffold at the stall capacity of the hoist whichever is greater)

This provision provides design criteria

27 T H RC I I N T E R N AT I O N A L CO N V E N T I O N A N D T R A D E SH OW bull MAR C H 15 shy 2 0 2012 CO H E N bull 179

OSHA Requirements

Standard 191028

Standard 191066

Standard 1926

for construction is governed by OSHA 29 CFR 1926 Subpart L Scaffolds Standards 1926450 1926451 and 1926452 and asso-ciated appendices as referenced in each section of the standard

bull Fall protection for construction with the use of temporary suspended scaffolding is governed by 29 CFR 1926 Subpart M Fall Protection

All OSHA standards are available online at wwwoshagov

In addition to these standards OSHA publishes official responses to questions submitted in writing by the public that are considered important clarifications to the published standard Standard Interpretashytions is an important resource for resolving unstated or unclear provisions of the OSHA standards Standard Interpretations is also available online

In 2001 the IWCA published the first edition of the ANSIIWCA I-141 Window Cleaning Safety Standard The standard includes guidelines for access to faccedilades for maintenance-type activities The standard provides detailed safety guidelines for the use of window-cleaning access equipment including the design certification and test-ing requirements for anchorages

The IWCA standard is available for pur-chase online at wwwiwcaorg

CONSTRUCTION VERSUS MAINTENANCE

OSHA Standard 191066(a) states ldquoBuilding maintenance includes but is not limited to such tasks as window cleaning caulking metal polishing and reglazingrdquo A Standard Interpretation dated 11182003 clarifies that work is considered mainte-nance if it involves ldquokeeping equipment working in its existing state or preventing its failure or decline In addition the con-cept of one-for-one replacement versus improvement as well as the scale and com-plexity of the project are relevantrdquo

According to OSHA the distinction appears to hinge on whether an improve-ment or an alteration is being made and also on the size of the project It is possible to replace components of a building one for one and still have the work be considered a construction activity if the magnitude of the project is of long duration or financially sig-nificant Since it may be unclear if a project represents ldquoconstructionrdquo or ldquomaintenancerdquo and since OSHA is not policing on the per-

mitting side of the project the conservative decision might be to follow the OSHA stan-dards that are the most demanding This would result in the designer following the structural requirements of either OSHA Standard 191066 or 1926 which are essentially identical as Standard 191028 lacks specific design requirements

DESIGN REQUIREMENTS

The following are excerpts from the OSHA standards that are related to the design of roof access anchors

191028(a)(4) Scaffolds and their components shall be capable of sup-porting without failure at least four times the maximum intended load

The intended load is either the load from the personal fall protection line or the sus-pended scaffold tieback line

191066(f)(3)(ii)(C) Each trans-portable outrigger shall be secured with a tie-down to a verified anchor-age on the building during the entire period of its use The anchorage shall be designed to have a stability factor of not less than four against overturning or upsetting of the out-rigger

The load that causes the overturning is not defined by this provision

191066(f)(3)(iii)(A) Davits Every davit installationmdashfixed or trans-portable rotatable or nonrotatablemdash shall be designed and installed to insure [sic] that it has a stability fac-tor against overturning of not less than four

The load that causes the overturning moment is not defined in this provision

191066 Appendix C I(c)(10) Anch-orages to which personal fall arrest equipment is attached shall be capable of supporting at least 5000 pounds per employee attached or shall be designed installed and used as part of a complete personal

fall arrest system which [sic] main-tains a safety factor of at least two under the supervision of a qualified person

The 5000-lb load is interpreted as an ultimate load The components that resist this load shall do so without failure Complete fall arrest systems are not the subject of this paper

1926451(a)(1) Except as provided in paragraphs (a)(2) (a)(3) (a)(4) (a)(5) and (g) of this section each scaffold and scaffold component shall be capable of supporting without fail-ure its own weight and at least four times the maximum intended load applied or transmitted to it

This provision is for the suspended scaf-fold equipment including the platform and the platform components

1926451(a)(2) Direct connections to roofs and floors and counterweights used to balance adjustable suspen-sion scaffolds shall be capable of resisting at least four times the tip-ping moment imposed by the scaf-fold operating at the rated load of the hoist or 15 (minimum) times the tipping moment imposed by the scaffold operating at the stall load of the hoist whichever is greater

This provision is used to determine the amount of the counterweights needed for the back span of the suspended scaffold outrigger beams The stall load of the hoist motor can be obtained from the hoist man-ufacturer

1926451(d)(1) All suspension scaf-fold support devices such as outrig-ger beams cornice hooks parapet clamps and similar devices shall rest on surfaces capable of support-ing at least four times the load imposed on them by the scaffold operating at the rated load of the hoist (or at least 15 times the load imposed on them by the scaffold at the stall capacity of the hoist whichever is greater)

This provision provides design criteria

27 T H RC I I N T E R N AT I O N A L CO N V E N T I O N A N D T R A D E SH OW bull MAR C H 15 shy 2 0 2012 CO H E N bull 179

IWCA Requirements

Appendix C

Summary of OSHA and IWCARequirements for the Structural Designof Anchorages

for checking the existing structure for verti-cal and lateral loads imparted by the sus-pended scaffold equipment

1926502(d)(9)(i) Except as provided in paragraph (d)(9)(ii) of this section when vertical lifelines are used each employee shall be attached to a sep-arate lifeline

1926502(d)(15) Anchorages used for attachment of personal fall arrest equipment shall be independent of any anchorage being used to sup-port or suspend platforms and capa-ble of supporting at least 5000 pounds per employee attached or shall be designed installed and used as follows

1926502(d)(15)(i) as part of a com-plete personal fall arrest system which [sic] maintains a safety factor of at least two

Complete fall arrest systems are not dis-cussed in this paper The 5000-lb load is interpreted as an ultimate load The anchors used for fall arrest equipment should be designed for this load without failure

The following are excerpts from the IWCA standard that are related to the design of roof access anchors

5821 Suspension Devices for Transportable Suspended Powered Platforms

(a) Suspension to permanent equip-ment or anchorages shall be in a straight line with no more than 15 degrees angulation (see appendix) in either direction

In the event of an equipment failure if the cable is more than 15ordm from a straight line to the edge of the roof as the cable moves laterally to a straight position the equipment will drop vertically and swing laterally This provision is intended to reduce this hazard OSHA does not have a similar provision

911 Anchorages shall be capable of sustaining a 5000-pound minimum load or a minimum 4-to-1-safety

factor whichever is greater in any direction that a load may be applied

The 5000-lb load and a design load with a 4-to-1-safety factor are interpreted as ultimate loads The anchors used for roof access should be designed for this load without failure

912 Anchorages if used for more than one lifeline shall have the load factor multiplied by each user

1721 Davits may be used to sup-port window cleaning activities pro-viding they are not used within ten feet of high-voltage lines and

a) The davit is designed by a regis-tered professional engineer

b) The davit has a stability factor of at least 4 to 1 against overturn-ing Each davit shall be designed to support an ultimate load of not less than four times the rated load (based on the rated load of the hoist when support-ing a powered access platform)

This provision is similar to OSHA OSHA does not have a provision that the roof access anchor must be designed by a regis-tered professional engineer As stated previ-ously the design loads are ultimate

Ideally anchors are to be placed in line with the suspended worker(s) Where this is impracticable anchors may be offset not more than 15 degrees from in line (perpendicular) provided displacement of the rope under load can be prevented

This provision allows an offset not more than 15deg and also requires that cable or stays are used to prevent the cable or life-line from straightening in the event of an accident

Two related but separate requirements are provided in OSHA regulations personal fall arrest or lifeline anchorages and equip-ment anchorages for the suspension scaf-fold equipment The regulations provide

design forces for each application The OSHA regulations for personal fall

arrest anchorages require a minimum strength of 5000 lbs per worker Multiple workers can be anchored to a single roof access anchor provided the anchor is designed for such access Roof access anchors shall be independent of any anchorage being used to suspend scaffold equipment

The OSHA regulations for roof access anchors for equipment tiebacks require a minimum strength of four times the rated load of the scaffold hoist motor Based on these criteria a roof access anchor used for equipment tieback that is designed for 5000 lbs can support a suspended scaffold with a hoist motor rated no higher than 1250 lbs

The IWCA standard provides guidance on roof access anchor layout stating that anchors may be located no more than 15deg from a perpendicular line to the roof edge This provision can be violated provided cable stays are installed to prevent the life-line from straightening out in the event of a failure

The combined requirement that person-al fall arrest anchors for each worker must be independent of equipment anchorages and that anchorages may be located no more than 15deg from a perpendicular line to the roof edge can result in a significant number of permanent roof access anchors Detailed layout studies are necessary to provide the number of anchors that meet the requirement of the OSHA and IWCA provisions in order to minimize the number of anchors

Factors to consider when developing an anchorage layout that meets the design requirements include the following

bull Each suspended scaffold platform requires two faccedilade access anchors for the platform equipment and one faccedilade access anchor for each work-er (unless each anchor is designed for multiple workers)

bull Faccedilade access anchors for suspend-ed scaffolding equipment cannot be used simultaneously by two differ-ent setups

bull Consider placement of faccedilade access anchors near the center of the roof to provide maximum offset from the roof edge in order to have wider cov-erage (the IWCA 15-degree rule) Roof anchors should be placed at least 6 ft from the roof edge unless

180 bull CO H E N 27 T H RC I I N T E R N AT I O N A L CO N V E N T I O N A N D T R A D E SH OW bull MAR C H 15 shy 2 0 2012

OSHA Requirements

Standard 191066

Appendix C to 191066

Appendix C to 1926

IWCA Requirements

8 Inspection and Testing

fall protection is provided along the rood edge Locating faccedilade access anchors in the center of the roof will also allow use from each side of a building

bull Rooftop equipment may represent an obstruction for clean efficient layout of faccedilade access anchors If the equipment frame cannot be used as an anchorage point anchors will be required to avoid the equipment

EVALUATION AND TESTING REQUIREMENTS FOR ANCHORAGES

191066(g) Inspection and tests

191066(g)(1) Installations and alter-ations All completed building main-tenance equipment installations shall be inspected and tested in the field before being placed in initial service to determine that all parts of the installation conform to applica-ble requirements of this standard and that all safety and operating equipment is functioning as required A similar inspection and test shall be made following any major alteration to an existing instal-lation No hoist in an installation shall be subjected to a load in excess of 125 percent of its rated load

OSHA does not include loading require-ments for the testing of the roof access anchors for permanent powered mainte-nance platforms The 125 of rated load is for the hoist equipment

191066(g)(2) Periodic inspections and tests

191066(g)(2)(i) Related building supporting structures shall undergo periodic inspection by a competent person at intervals not exceeding 12 months

191066(g)(2)(ii) All parts of the equipment including control sys-tems shall be inspected and where necessary tested by a competent person at intervals specified by the manufacturersupplier but not to

exceed 12 months to determine that they are in safe operating condition Parts subject to wear such as wire ropes bearings gears and gover-nors shall be inspected andor test-ed to determine that they have not worn to such an extent as to affect the safe operation of the installation

191066(g)(2)(iii) The building owner shall keep a certification record of each inspection and test required under paragraphs (g)(2)(i) and (ii) of this section The certification record shall include the date of the inspec-tion the signature of the person who performed the inspection and the number or other identifier of the building support structure and equipment which [sic] was inspect-ed This certification record shall be kept readily available for review by the Assistant Secretary of Labor or the Assistant Secretaryrsquos represen-tative and by the employer

II(b)(2) The anchorage should be rigid and should not have a deflec-tion greater than 04 inches when a force of 2250 pounds is applied

I(b)(2) The anchorage should be rigid and should not have a deflection greater than 004 inches when a force of 2250 pounds is applied

The loading described in these two sec-tions is used to measure the stiffness of the roof-anchor assembly

811 Newly Installed Equipment

(a) Before initial use by the window cleaner(s) the following equip-ment (as provided for a specific building) shall be successfully demonstrated by the vendor with the rated load under the com-plete range of operation and be so certified in writing 1) Permanently installed access

platform(s) or its supporting fixtures

2) Anchorages

812 Inspection and Retesting of Existing Equipment and Systems

(a) Before each use all components of a window cleaning equipment support system permanently dedicated to the building shall be visually inspected by a com-petent person Any signs of excessive wear weld or material cracks bent distressed or rust-ed metals corrosion or abraded fibers shall be cause for more extensive inspection or testing before continued use

(b) A record of all inspections test-ing certifications modifications and repairs shall be documented in a dedicated log book

(c) The certification record shall include the date of the inspec-tion and test and the signature of the inspector

813 Minimum Inspection and General Testing Criteria

(a) Fall arrest components shall be inspected and tested as pre-scribed by ANSI Z3591

(b) Anchorages shall be inspected in accordance with Section 8 Designated anchorages targeted for post-installation testing shall be tested by applying a minimum static load of twice the design load in each (primary) direction that a load may be applied For example anchor-ages designed for a 5000-pound ultimate load shall be tested at 2500 pounds

The design load is the static force imparted on the system a 5000-pound ultimate load with a factor of safety of four equates to a 1250-pound static load for the personal fall-arrest system It is common practice to test post-installed anchors to 150 of the static load Testing these sys-tems to 200 of the static load is reason-able provided a deflection criteria is also included as is required by OSHA 191066

27 T H RC I I N T E R N AT I O N A L CO N V E N T I O N A N D T R A D E SH OW bull MAR C H 15 shy 2 0 2012 CO H E N bull 181

OSHA Requirements

Standard 191066

Appendix C to 191066

Appendix C to 1926

IWCA Requirements

8 Inspection and Testing

fall protection is provided along the rood edge Locating faccedilade access anchors in the center of the roof will also allow use from each side of a building

bull Rooftop equipment may represent an obstruction for clean efficient layout of faccedilade access anchors If the equipment frame cannot be used as an anchorage point anchors will be required to avoid the equipment

EVALUATION AND TESTING REQUIREMENTS FOR ANCHORAGES

191066(g) Inspection and tests

191066(g)(1) Installations and alter-ations All completed building main-tenance equipment installations shall be inspected and tested in the field before being placed in initial service to determine that all parts of the installation conform to applica-ble requirements of this standard and that all safety and operating equipment is functioning as required A similar inspection and test shall be made following any major alteration to an existing instal-lation No hoist in an installation shall be subjected to a load in excess of 125 percent of its rated load

OSHA does not include loading require-ments for the testing of the roof access anchors for permanent powered mainte-nance platforms The 125 of rated load is for the hoist equipment

191066(g)(2) Periodic inspections and tests

191066(g)(2)(i) Related building supporting structures shall undergo periodic inspection by a competent person at intervals not exceeding 12 months

191066(g)(2)(ii) All parts of the equipment including control sys-tems shall be inspected and where necessary tested by a competent person at intervals specified by the manufacturersupplier but not to

exceed 12 months to determine that they are in safe operating condition Parts subject to wear such as wire ropes bearings gears and gover-nors shall be inspected andor test-ed to determine that they have not worn to such an extent as to affect the safe operation of the installation

191066(g)(2)(iii) The building owner shall keep a certification record of each inspection and test required under paragraphs (g)(2)(i) and (ii) of this section The certification record shall include the date of the inspec-tion the signature of the person who performed the inspection and the number or other identifier of the building support structure and equipment which [sic] was inspect-ed This certification record shall be kept readily available for review by the Assistant Secretary of Labor or the Assistant Secretaryrsquos represen-tative and by the employer

II(b)(2) The anchorage should be rigid and should not have a deflec-tion greater than 04 inches when a force of 2250 pounds is applied

I(b)(2) The anchorage should be rigid and should not have a deflection greater than 004 inches when a force of 2250 pounds is applied

The loading described in these two sec-tions is used to measure the stiffness of the roof-anchor assembly

811 Newly Installed Equipment

(a) Before initial use by the window cleaner(s) the following equip-ment (as provided for a specific building) shall be successfully demonstrated by the vendor with the rated load under the com-plete range of operation and be so certified in writing 1) Permanently installed access

platform(s) or its supporting fixtures

2) Anchorages

812 Inspection and Retesting of Existing Equipment and Systems

(a) Before each use all components of a window cleaning equipment support system permanently dedicated to the building shall be visually inspected by a com-petent person Any signs of excessive wear weld or material cracks bent distressed or rust-ed metals corrosion or abraded fibers shall be cause for more extensive inspection or testing before continued use

(b) A record of all inspections test-ing certifications modifications and repairs shall be documented in a dedicated log book

(c) The certification record shall include the date of the inspec-tion and test and the signature of the inspector

813 Minimum Inspection and General Testing Criteria

(a) Fall arrest components shall be inspected and tested as pre-scribed by ANSI Z3591

(b) Anchorages shall be inspected in accordance with Section 8 Designated anchorages targeted for post-installation testing shall be tested by applying a minimum static load of twice the design load in each (primary) direction that a load may be applied For example anchor-ages designed for a 5000-pound ultimate load shall be tested at 2500 pounds

The design load is the static force imparted on the system a 5000-pound ultimate load with a factor of safety of four equates to a 1250-pound static load for the personal fall-arrest system It is common practice to test post-installed anchors to 150 of the static load Testing these sys-tems to 200 of the static load is reason-able provided a deflection criteria is also included as is required by OSHA 191066

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9 Anchorages and Fall Protection

Summary of OSHA and IWCARequirements for the Inspection andTesting of Anchorages

919 Anchorages shall be inspected annually by a qualified person Anchorages shall be recertified when reroofing or renovating (pertinent to the window-cleaning system) or at periods not to exceed 10 years The report of this inspection shall be included in the buildingrsquos log book If during the anchoragersquos inspec-tion an area of suspicion is identi-fied a test procedure if necessary shall be performed under the approval of a registered professional engineer

9110 Certification and recertifica-tion of anchorages shall be under the supervision of a registered pro-fessional engineer

Property owners must keep on site a written record of each inspection and test performed so that it is available for review

OSHA requires that all anchorages be tested before being used for the first time Retesting is not required unless there is a ldquomajor alterationrdquo Periodic inspection by a competent person at a minimum shall occur every 12 months A competent person is one who is capable of identifying existing and predictable hazards in the surround-ings or working conditions and who has the authority to take prompt corrective mea-sures to eliminate them

OSHA leaves the specific requirements of structural testing to the judgment of the qualified person A qualified person is one who by possession of a recognized degree certificate or professional standing or who by extensive knowledge training and expe-rience has successfully demonstrated the ability to solve or resolve problems related to the subject matter the work or the project

IWCA requires that anchorages be inspected annually by a qualified person IWCA additionally requires that anchorages be certified (ie tested) before initial use after reroofing after modification of the win-dow-cleaning system when upon inspec-tion distress or damage is identified and at periods not to exceed ten years

IWCA requires that roof access anchors be tested by applying a static load of twice the ldquodesignrdquo load in each direction that the

load may be applied This means that for personal fall-arrest anchorages the re-quired applied load is 2500 lbs and for equipment tieback anchorages it would appear to require for instance a minimum applied load of 2000 lbs for a swing stage with a hoist motor rated at 1000 lbs though anchorages are typically tested with an applied load of 2500 lbs under the IWCA requirements

OSHA requires that the anchorage for permanent house rig equipment and for per-manent tieback and fall protection anchor-ages not have a deflection greater than 004 in when a force of 2250 lbs is applied

TESTING STANDARDS Roof access anchors are required to be

tested in the direction of anticipated load-ing In most installations the roof access anchor would be loaded towards the roof edge in the event of a failure We have often reviewed proposed testing procedures sub-mitted by reputable anchor installers that detail testing procedures for parallel-to-roof testing Parallel-to-roof testing often requires a cable and a jack that allows the anchors to be pulled towards each other (Photo 10) Parallel-to-roof-edge testing vio-lates the requirements of IWCA Standard 813(b) which states that the test load must be applied in each primary direction that a load may be applied In the event of an equipment failure the direction of force

will be perpendicular to and toward the roof edge

Testers complain that it is ldquoimpossible to test in the direction required by IWCArdquo Although it takes additional effort to test in the required direction it is not impossible

In our experience checking the status of existing faccedilade access anchors before using suspended scaffolding building own-ers typically lack awareness that they are responsible for providing a written record of each inspection and test for anchorages In such instances the faccedilade access anchors should be reevaluated an effort that might have been unnecessary had the building owner maintained adequate records

FUTURE DEVELOPMENTS The Architectural Engineering Institute

(AEI) of the American Society of Civil Engineers (ASCE) is currently scheduled to publish a guideline for the design evalua-tion and testing of faccedilade access installa-tions in the fall of 2012 The objective of the guideline is to provide guidance to architec-tural and structural engineers on the struc-tural loading that should be considered in the design evaluation and testing of struc-tural members that are part of faccedilade access installations

The IWCA is currently working on a revised edition of its inaugural 2001 edition The publication date has not been made public

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Photo 10